Stmjes ratent office



Aug 10', 1954 R. H. CURTIS 2,685,969

FILTER ELEMENT Filed July 15, 1949 Patented Aug. 10, 1954 ,FILT-ERELEMENT Cltusse'lP'H. GurtisfSt. Charles,A Ill., assgnor to 'Application,July-'13, 1949,-- Serial .Nm y104,474

14 Claim; (Cl. 210-1-169) l Thi's invention relates toltersmade fbr'ousmaterials', and' particularly toreplaceable "lter elements'l for use'inliquid systems.

fIt isan object'ofthis'invention tojprovide a Vl2 casingl on a vreducedscale. .showing the removal of` a.filter element from thac'asing; and

Fig. 5 represents one Ymethod .by .whichthe filter element. may bema'de.carcass'of fibrous iter element `of"onefpiece'molied .iibrous con- "5materialinitheshapeoftheiil'ter elementmay struction "'for use in"`liquid' systems. be' depositedY from theiwaterdispersion'fupontheAnothertobject Iof the 'present" invention; is i to perforated screen.provideaonemiecemoldedfbrous filter element 'Consideringtherdrawingsnown greaterdewhich may'be'simply and inexpensivelmprepared,taiL/in Fig. 1 one'form of themoldedbrous and"*vvliichmay'tie4discarded' after use. 1`0` lter element is shown in which theupper'bodyAnother 'obj ect is to 'provide a filter element ofiight"construction'which will' be'seifesupporting to resist asubstantial 'filtrationpressure lAurther obj ect' oftl'iis' invention'isto provide a `strong moldedbrous flterelement which will havesan'extensive4 surface f area." in contact Ywith the liquidl tobef -ltered.

-still vvfurther object "is "to lprovide a filter adapted'`v toi'berremovedfrom a 4casing with* the iilteredfsluiige contained'entirely Within' theit'er element sothat it "may "be removed for"disposal without contaminatingthe casing` or"the`i`1i"d circulatingsystem.

yEliie above objects "and other'oobj ects `and adf vantages of theinventonrvfillibecome"apparent uponffurther-examination of thedescription `and drawings.

The-1 presentl invention contemplates the fpreparati'on-*of a "thin'lterfelement which'may be readily #and inexpensively'f moldedifromr`conventional liibrous stocksI in'such'form-that it'w'illprovide "arelatively'fl'arge surface'l areato the contaminated liquid f and `atthe same Avti'rhe will have sucient structural 'strength toi resist`'Clistortion from ordinaryfiltration'pressures The" which 'the'iiil't'erf element. is" particularly" adapted'V is' in motorielsystems" toremove',se"diir1erit`from'Y fuels.

While the .form of theliilter .element o and the methods Vwhich may'beemployed' in the preparation thereof-are not"limitingV features of thepresentfinvention, a particular embodiment-'of tlaeinven-tion will beused inftheffollowing'fdesliliptiorrfandidrawings for illustrativepurposes ogy.

intthedrawings, Fig. 1 is a perspective View offene: :embodiment of theinvention :showing thexopen end; of the lter element attiiefptopanrilzthaluted Supportinglportiornat the fbottom:

.FF-ig. .Zisg-a gcrossrsectionaliviewvalong :the '1 line 242i:ofatheffilter element: oi' Eig. Tl;

3; isfza cross-fsectionalyiew': of thelte11 element of Fig. l-alongVtlf1eline..3.-3 looking downwardly into the' closed end f the filterelement; v

Fig. 4 A--is a side view of' a'feonventionalf Tilton-U60 Iterminates inthe'ange 2 at the open'end'of the rilter element. Inte'grally connected'with the upperbody l is the loweribody 3whi'chnar.- rows Ygradu ally atthe baseportion 4 terminating at the closed'end of the ii'lterelementl'.The upper body l is of thin construction, being'so'mewhat smoother on=the' inner surface" l6.

vThe lower bodyffis slightly 'smaller in' diam-eter' than2 the upper@body 1 l tov provideA free spaceor the fii'ow of` ltere'd" liquidzbetweeny the tilt-err element and the 'ltercasing. `Thelower bodyiscomposed of" a continuous series of :flutes varranged to lend support to*each adjacent flute; Inthis manner'a large surfaceareaf isprovidad, andat thesame time-the structural-strength; of thefbrousfiilter 'elementisi-increased". -The'iiutes extenddownwardlyi'romf tllelowerx bo'dy 3through the' baserportion-A andi' terminate ini the@ bottom portion'Tb'. Hence, the'base-portion `^l and 'fthe bottom f portion :"511likewise" have a largey 1 surface area plus thev structural Strength ofmutually supporting-'flutes y Figs. Zand Bislfiow the interior fthe-molded brous 'lil-ter I element -showingthe vflutes `1 L and thestepldown portionfbetween'theupper body is and' the-lower bofdy3;'In`Fig. f3?t soma o'fiftlie` iiutes 'l are shown terminating at thelower end offthe'fbasep'ortionill. `The flutes-"I arefresponsiblefor-thestructuralstrength ofi the elementzby virtue oft their mutually'supporting relation. rnvAdditionally; the f flutesfhasten the fdrainage' from the'iter element.-

iV graphicallyI represents the` removal of ai molded 'i fibrous filterelement f from f one' type .of

'iilterv casing. Tlieffilter casingg vis usually made of metalormolded?` plastic. "The'casingl consists ofi' ai topifiange U', ai body Il' and: a y base-portion' l2 having thereinl an opening-f i3' throughwhich the filtered liquidmay be eXhaustedfrom the casing. Thelsides-oflthe'upper body portion "l may`- bet vertical Aor tapered,` butshould preferably iitf snugly against the inside'` of the casing" f I:to form asealftherewith. In Fig. y'ithefiilorousf l- .ter elementisshowrr partially' removed position with the upper' body! exposedl andthelower body -3'f indicated byA the: 'dotted 1 line. 'Whenl the lterelement has reached' the end of its effective life, Aor "for -any otherreason, it maybe'simpl'y changed by removing the-top off tliefcasing andliitingi the ii-lterlementassshown Fig. -4`. The

Figure 4 also shows a modification of the filterillustrated in Figures1, 2 and 3. The modification consists of an integrally molded iiange I9,which can support the filter and also assists in forming a seal for theupper part of the filter.

A preferred apparatus for the preparation of the molded fibrous filterelement is illustrated in Fig. 5. A container I4 is filled with adispersion of fibers in water and the mold I5 is immersed therein. Themold I5 is composed of a heavy perforated body I6 which is roughly theshape of the finished article. Over the perforated body I6 is a screenI'I which is adapted to have the same shape as is desired in thefinished article. The application of reduced pressure to the mold I5through the inlet I8 causes a deposition of fibers from the dispersiononto the screen I'I. The water passes through the screen andy throughthe body I6 and is exhausted through the outlet I8. After a sufficientlayer of fibers has been deposited upon the screen the mold is removedfrom the dispersion and the molded fibrous element may be transferredfor drying or may be dried upon the form I5.

In use the molded fibrous filter element is inserted into a suitablydesigned filter casing in which the liquid to be filtered is introducedto the arearwithin the filter element and passes through the filterelement leaving any solid material lentrapped within the filter elementor between the fibers of the filterrelement. The cleaned liquid is thendischarged from the filter casing into the liquid system where it isused. When the filter element becomes dirty or has reached the end ofits useful life it may be easily removed and replaced with a cleanelement. Unlike the tube type of filter element in which the sludgeimpregnates the element throughout, and particularly at the outer edge,the present filter element retains the sludge within the cup portion ofthe element and makes disposal of the sludge much simpler. Furthermore,lthere is little possibility that the sludge may penetrate the filterelement and be reintroduced into the liquid system. Y

The type of fibrous material employed in the preparation of the subjectfilter element may be varied widely depending upon the availability ofmaterials and the characteristics desired in the finished product. Forexample, cellulosic fibers, wool fibers, spun glass fibers or' anysuitable combination of such fibers may be successfully used. Amongcellulosic fibers are included wood pulps such as Kraft pulp and sulfitepulp, cotton linters, wheat and oat straw, bagasse, esparto, and thelike. Synthetic fibers of many types are known which may be used aloneor blended with other types of fibers. Itis contemplated that onefamiliar with the pulp art will determine the type of fibrous materialbest suited to his purpose and employ the same in the practice of thisinvention. One satisfactory fibrous material is composed of 50% cottonlinters and 50% rag stock.

Wet-strength resins are well known in the paper pulp art and include avariety7 of chemical compositions. The better known `wet-strength resinsinclude a melamine-formaldehyde type of resinr and so-called vone-stagephenolic resins of the phenol-formaldehyde type. The phenolic resinshave the advantage of slightly improved water resistance and strengthoverthe melamine resins. The wet-'strength resins are to lbedistinguished from the coating resins in that the wetstrength resin willdeposit upon the fibers in such manner as not to clog the area betweenfibers while the coating type resins tend to clog or seal the areabetween fibers. Thus, it will be seen that the wet-strength resin may beemployed in a filter element, while the coating resin would be un-'treatment of the beaten dispersion of resin and fiber results in thedeposition of a film of resin. on the individual fibers. This resinimpregnated,

l fiber may be satisfactorily molded into the Yfinished product with theelimination of the suba sequent dipping step.

From the foregoing description ofthe invention and the drawings it willbe seen that a filter element having novel advantages andcharacteristics has been provided by the preparation of a one-piecemolded fibrous article having a large surface area and sufficientstrength to withstand ordinary filtration pressures.` The principalvadvantages of the present invention are in the preparation of aninexpensive filter element which may be readily changed and disposed of,and which is capable of cleaning a large volume 0f contaminated liquid.

The invention is hereby claimed as follows:

A filter comprising the combination of an impermeable generallycylindrical casing and a one-piece filter element of fibrous materialconsisting essentially of a generally cylindrical body having an openend and a closed end and permeably constructed of accreted fibersindividually coated with a wet-Strength resin, said body comprising inintegral relation a smooth elongated upper portion adjacent the open endfitting snugly in said casing with its exterior in contact throughoutwith the interior of said casing, ay

lower elongated portion of smaller diameter than said upper portion, abase portion corresponding to the closed end of said body, and aplurality of flutes in the sides of said lower portion ex-A tending intosaid base portion.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Y 669,129 Stukes Mar. 5, 1901 1,122,393 House Dec. 29, 19141,682,897 Fesler Sept. 4, 1-928 1,941,982 Gill Jan. 2, 1934 2,093,167Gray Sept. 14, 1937 2,147,792 Knight Feb. 21, 1939 2,298,674 BurhansOct. 13, 1942 2,298,980 Sloan et al. Oct. 23, 1942 2,337,575 Sloan etal. Dec. 28, 1943 2,348,725 Chaplin May 16, 1944 OTHER REFERENCESCollins: Wet Strength Paper, Paper Industry andl Paper World, June1943,H page 265.

